# Bell Graph - Stats

A colleague, who is a Fuels engineer, is testing the effects of an experimental fuel additive for petrol engines which your company is developing. She adds the same sample amount of additive to 100 full petrol tanks for the same model of car, and records the number of miles per gallon (mpg) for each car after being driven around a test track at a constant speed, until the fuel runs out. She knows that such testing undertaken without the additive produces a mean mpg figure of 44. Collecting results with the additive, she notices that the mean mpg figure is 48 with a sample standard deviation of 13 mpg.
By interpreting the results of the testing, show whether you agree, or not, with her hypothesis that the fuel additive has influenced the number of miles per gallon for the cars.
Draw by hand, or use suitable software, to produce a graphic, suitable for a non-
technical company executive, which represents the results of your analysis.

I believe I have answered this question but I just don't understand how I can make a graph with 2 mean values ?
Original post by cookn
A colleague, who is a Fuels engineer, is testing the effects of an experimental fuel additive for petrol engines which your company is developing. She adds the same sample amount of additive to 100 full petrol tanks for the same model of car, and records the number of miles per gallon (mpg) for each car after being driven around a test track at a constant speed, until the fuel runs out. She knows that such testing undertaken without the additive produces a mean mpg figure of 44. Collecting results with the additive, she notices that the mean mpg figure is 48 with a sample standard deviation of 13 mpg.
By interpreting the results of the testing, show whether you agree, or not, with her hypothesis that the fuel additive has influenced the number of miles per gallon for the cars.
Draw by hand, or use suitable software, to produce a graphic, suitable for a non-
technical company executive, which represents the results of your analysis.

I believe I have answered this question but I just don't understand how I can make a graph with 2 mean values ?

Got this moved to Study help and edited the title slightly for you to get better replies

Take care.
I too am struggling with the graph, did you ever it resolved?

great website.
Original post by gtdub1234

This is the moved post
Original post by gtdub1234

great website.

You just have to look at the URL of your browser?
https://www.thestudentroom.co.uk/showthread.php?t=6722710

@cookn, I don't know the context but it seems it wants you to state a null-hypothesis, calculate a p-value and a confidence interval as well. I'd actually just have a simple infographic which showed the two means and also gave percentage uncertainties for each of them (since you can calculate the standard error).
So I'm struggling with this too. Anyone have any feed back? I have created a graph that shows the means and the 1st standard deviation. apart from that I can't think what else to put in.
Did this ever get answered? I have completed the question relative to this but am also struggling with the graph.
Without seeing the full question we’re working a little in the dark here…

I do love the strange idea that we can make a non-technical person understand hypothesis testing by drawing a picture.